Apparatus for finishing the edges of wallboard



Nov. 21, 1939. c, 5, WALPER 2,180,570

APPARATUS FOR FINISHING THE EDGES 0F WALLBOARb INVENTOR= fliav ATT RNE).

CURRYORA WALPER V Patented Nov. 21, 1939 PATENT OFFICE APPARATUS FOR FINISHING THE EDGES OF WALLBOARD Curry Ora Walpenliamilton, Ontario, Canada Application July 16, 193'7,- Serial No. 154,048 In Canada July 18, 1936 9 Claims. (21. 51 -80) This invention. relates to an apparatus for finishing the edges of wallboard by grinding.

As is well known, in the manufacture of plaster wallboard, a plaster core is enclosed within two paper liners which are folded around the longitudinal edges of the board, the transverse edges being however unenclosed. The plaster core exposed along the transverse edges usually presents a rough uneven appearance andthe need 10. of some means for trimming these edges in order to obtain a finished lookingproduct has long been recognized. Various methods of finishing the board by grinding or cutting these edges have been suggested but have been found unsatisfacld; tory due to resultant damage to the board during the finishing operation. a The present invention has for its object to provide a method and apparatus for continuously and automatically grinding off the uneven trans- 20 verse edges of wallboards whereby the edges are not broken down or damaged and present a smooth finished appearance.

The invention will be described with reference to the accompanying drawings in which, 5 1 Figure 1 is a plan view of an apparatus embodying the invention,

Figure 2 is an elevation on line 2-2 of Figure 1,

Figure 3 is partial side elevation, 30 Figure 4 is a side elevation of a grinding unit, Figure 5 is a side elevation of a clutch operating detail, I

Figure 6 is a plan of the detail shown in Figure 5, 35 Figure '7 is a diagrammatic section showing the beginning of the grinding operation Figure 8 is a diagrammatic section showing the completion of the grinding operation, and Figure 9 is a sectional elevation of another 40 clutch operating detail.

' In the drawings, 1 is a roller conveyor adapted to receive the boards to be ground mounted on a suitable framework 2, 3 a pair of cooperating transverse chain conveyors adapted to engage and 45 convey the boards transversely of the roller conveyor l whereby their transverse edges are engaged by a pair of grinders 4 mounted in the framework 2, 5 is a transverse board supporting roller, 6 a short roller cooperating with transverse 50 roller S-during passage of a board therebetween to steady the same during the grinding operation and 1 a set of transverse rollers adapted to receive the completed boards. Some or all of the rollers in conveyor- I may be driven in any 55} suitable manner. A stop I for the boards at carried by the frame 2.

The cross chain conveyors 3 are carried by sprockets 8, one pair of which are mounted on a single shaft 8' extending across the machine and 5 mounted in the frame 2 as shown. Each conveyor 3 is provided with a plurality of cooperating board engaging dogs 9 and guides 10 for the same may be provided at the upper portions of the conveyors. The conveyors 3 are driven from a shaft ll 10 by means of sprockets l2 and chain l3.

The grinders 4 comprise a grinding cylinder l4 composed of one or more sections mounted on a shaft I5 carried by an inclined frame l6 whereby the grinding cylinder, I4 is parallel to the length of but inclined with respect to the horizontal plane of the cross conveyors 3. The grinding cylinders M are continuously driven-from the drive shaft I! of a motor l8 by means of a belt drive l9 to a main shaft mounted in bearings 2| 20 carried by frame 2 and having a pair of bevel gears 22 thereon meshing with a second pair of bevel gears 23 carried by shafts 24 mounted in the grinder frames l6, shafts 24 having connection with the grinding cylinder shafts l5 by 25 means of V-belt 25 and pulleys 26. A frame member comprising a plate l6 supports the edges of the boards during the grinding operation.

The cross conveyors 3 are arranged to be actuated only when a board is properly positioned thereon as indicated at 2' in broken lines in Figure 1 and means for accomplishing this will now be described. A trip plate 2'! is pivotally carried by a rod 28 mounted in the frame 2 adjacent the stop I' and is normally'held in an upright position with the top portion thereof abutting the adjacent conveyor guide III by means of a. spring 23 secured to frame 2. Secured to one end of the rod 28 is a cam 30 having cooperative relation with a lever 3| the free end of which extends over the adjacent conveyor 3 and which is pivotally carried by a collar 32 keyed to the upper end of a vertical shaft 33 which is rotatively mounted in the frame 2. A spring 3| urges the lever 3| into bearing relation with the cam 30. Secured to the vertical shaft 33 is an arm 34 operatively connected with a linkage 35 connected to a clutch member 36 slidingly keyed to shaft l I. As shown in Figure 9,- the linkage 35 includes a .link 43 having a sliding pivotal connection with the arm 34 by means of a pin 44 on link 43 extending through a slot 45 in arm 34. The link 43 is pivoted at 46 to a second link which is pivoted to the frame at 48. The link 41 has a loose pivotal connection with the clutch 5 member 36 whereby swinging of the link 41 on pivot 48 will tend to slide the clutch member 36 on the shaft Ii. This .loose pivotal connection comprises a portion 49 of the link 41 which extends around either side of the clutch member and pins 59 carried by the portion 49 and loosely seated in the clutch member. A cooperating clutch member 36 is loosely mounted on shaft H and is continuously driven by means of sprockets 3i and chain 38 from a shaft 39 mounted on frame 2 and driven by a belt 40 from the driven grinder shaft 20. A spring 4| urges the clutch members 36 and 36. into engagement with each other.

It will be noted that the free end of .lever 31 is arranged to be raised or lowered by the cam 30, which is actuated by the trip, plate 21, and in its raised position is adapted to clear the dogs 9 of the cross conveyor whereas in its lowered position it is adapted to be engaged by a dog 9. Thus, when the trip plate is in its normal upright position, as shown in Figure 2, the lever 3| will be in its lower position, as shown in dotted lines in Figure 5, and will have previously been engaged by a dog 9 to swing it in a clockwise direction and rotate the shaft 33 to disengage the clutch members 36 and 35 and stop movement of the conveyors 3. When the end of a board engages the trip plate 2'3 and places it in a horizontal position, as shown in Figure l, the lever '3! will be raised by the cam 30 out of engagement with the dog 9 and the spring M will be free to efiect engagement of the clutch members 36 and 36, whereupon the conveyors 3 will be actuated to engage the board and carry it transversely into engagement with the grinders 4. Engagement of the clutch members will of course act to swing thelever (ii in an anti-clockwise direction back to its previous position. As soon as the board passes out of engagement with the trip plate, the latter springs back into upright position, lowering the lever 3i, which is then in position to be engaged by the next dog on the conveyor to stop the same.

One or more collars 42 may be provided on certain rollers of the conveyor l to effect tilting of the inner sides of an incoming board upwardly to clear the board just being carried ofi by the cross conveyor 3. Thus, boards may be fed into the apparatus quickly enough to trip the plate 2i before the succeeding dog has engaged the lever 3!.

An important feature of the invention resides in the inclined mounting of the grinding cylinders I i, As diagrammatically illustrated in Figures '7 and 8, this mounting results in an initial grinding engagement between the cylinder and board at the upper corner only of the board edge and a gradual engagement of the remaining portion of the edge, the lower corner being finally engaged and finished off. Breakage of and damage to the edges of the board, which would frequently occur with a horizontal mounting of the grinding cylinders, is avoided as a result of the inclined mounting described.

I claim: 1

1. Apparatus for grinding the edges of wallboard comprising a conveyor for the wallboard, a second conveyor extending transversely of the first conveyor, cylindrical grinders adjacent the second conveyor, the axes of said cylindrical grinders being parallel to the length of but inclined with respect to the horizontal plane of the second conveyor, means for driving said cylindrical grinders continuouslv and means. for actuating the second conveyor only when a wallboard has reached a predetermined position thereupon.

2. Apparatus for grinding the edges of wallboard comprising a roller conveyor for the wallboard, a chain conveyor extending transversely thereof and adapted to convey wallboard transversely therefrom, grinding means mounted adjacent the outer limits of the chain conveyor and. adapted to engage the transverse edges of wallboard upon said chain conveyor, the axes of said grinding means being parallel to the length of but inclined with respect to the horizontal plane of the chain conveyor, means for driving the chain conveyor, clutch means normally effecting driving engagement between said driving means and the chain conveyor, and a lever arranged to engage the chain conveyor and to be actuated thereby to disengage said clutch means. I

' 3. Apparatus as defined in claim 2 wherein wallboard engaging means are provided on said roller conveyor and are adapted to maintain said lever out of engagement with the chain conveyor during engagement of a wallboard therewith.

4. Apparatus for grinding the edges of wallboard comprising a roller conveyor for the, wallboard, a chain conveyor extending transversely of the roller conveyor and having dogs adapted to engage wallboard and convey the same transversely thereof, cylindrical grinders mounted adjacent the outer limits of the chain conveyor and adapted to engage the transverse edges of wallboard upon the said conveyor, the axes of said cylindrical grinders being parallel to the length of but inclined with respect to the horizontal plane of the chain conveyor, means for driving said cylindrical grinders, means for driving the-chain conveyor, clutch means normally effecting driving engagement between said conveyor driving means and the chain conveyor, a lever arranged to engage the chain conveyor and to be actuated thereby to disengage said clutch means, cam means arranged to move said lever out of engagement with the chain conveyor, and a trip plate mounted in said roller conveyor and arranged to actuate said cam means said trip plate being engageable by wallboard upon said roller conveyor.

5. Apparatus for grinding the edges of wallboard comprising a conveyor for the wallboard, a second conveyor extending transversely of the first conveyor and adapted to carry the wallboard in a direction at right angles to its direction of movement on said first conveyor, grinding means mounted adjacent the outer limits of said second conveyor and adapted to engage the edges of wallboard upon said second conveyor, and means responsive to a predetermined positioning of a wallboard on said second conveyor for actuating the latter.

6. Apparatus for grinding the edges of Wallboard comprising a conveyor for the wallboard, a second conveyor extending transversely of the first conveyor and adapted to carry the wallboard in a direction at right angles to its direction of movement on said first conveyor, cylindrical grinders mounted adjacent the outer limits of said second conveyor and adapted to engage the edges of wallboard upon the second conveyor, means for driving the second conveyor, clutch means normally effecting driving engagement between said conveyor driving means and the second conveyor and means arranged to be operated by said second conveyor for disengaging said clutch means 7. Apparatus as defined in claim 6 wherein means are provided engageable by wallboard on the first conveyor for maintaining said last mentioned means out of operative engagement with the second conveyor.

8. Apparatus for grinding the edges of wallboard comprising a conveyor for the wallboard, a second conveyor extending transversely of the first conveyor, cylindrical grinders mounted adjacent the outer limits of said second conveyor, means for driving the second conveyor, clutch means normally efiecting engagement between said conveyor driving means and the second con-v veyor, a lever arranged to engage the second conveyor and to be actuated thereby to disengage said clutch means, cam means arranged to move said lever out of engagement with the second means, said trip member being engageable by wallboard upon the first conveyor.

9. Apparatus for grinding the edges of Wallboard comprising a conveyor for the wallboard, grinding means mounted adjacent the outer limits of said conveyor and adapted to engage the edges of wallboard upon said conveyor, means adapted to position a wallboard on said conveyor, and means responsive to a predetermined positioning of a wallboard on said conveyor for actuating the latter.

CURRY ORA WALPER. 

